Leads with electrode carrier for segmented electrodes and methods of making and using

ABSTRACT

A stimulation lead includes a lead body having a longitudinal length, a distal portion, and a proximal portion; terminals disposed along the proximal portion of the lead body; an electrode carrier coupled to, or disposed along, the distal portion of the lead body; segmented electrodes disposed along the electrode carrier; and conductors extending along the lead body and coupling the segmented electrodes to the terminals. The electrode carrier includes a lattice region defining segmented electrode receiving openings. Each of the segmented electrodes extends around no more than 75% of a circumference of the lead and is disposed in a different one of the segmented electrode receiving openings of the electrode carrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/517,599 filed Oct. 17, 2014, which issued as U.S. Pat. No. 9,227,050,which is a continuation of U.S. patent application Ser. No. 13/951,057filed Jul. 25, 2013, which issued as U.S. Pat. No. 8,897,891 on Nov. 25,2014, which claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application Ser. No. 61/679,264 filed on Aug. 3,2012, all of which are incorporated herein by reference.

FIELD

The invention is directed to the area of electrical stimulation systemsand methods of making and using the systems. The present invention isalso directed to electrical stimulation leads with segmented electrodesthat can be used for directed electrical stimulation, as well as methodsof making and using the segmented electrodes, leads, and electricalstimulation systems.

BACKGROUND

Electrical stimulation can be useful for treating a variety ofconditions. Deep brain stimulation can be useful for treating, forexample. Parkinson's disease, dystonia, essential tremor, chronic pain.Huntington's Disease, levodopa-induced dyskinesias and rigidity,bradykinesia, epilepsy and seizures, eating disorders, and mooddisorders. Typically, a lead with a stimulating electrode at or near atip of the lead provides the stimulation to target neurons in the brain.Magnetic resonance imaging (“MRI”) or computerized tomography (“CT”)scans can provide a starting point for determining where the stimulatingelectrode should be positioned to provide the desired stimulus to thetarget neurons.

After the lead is implanted into a patient's brain, electrical stimuluscurrent can be delivered through selected electrodes on the lead tostimulate target neurons in the brain. Typically, the electrodes areformed into rings disposed on a distal portion of the lead. The stimuluscurrent projects from the ring electrodes equally in every direction.Because of the ring shape of these electrodes, the stimulus currentcannot be directed to one or more specific positions around the ringelectrode (e.g., on one or more sides, or points, around the lead).Consequently, undirected stimulation may result in unwanted stimulationof neighboring neural tissue, potentially resulting in undesired sideeffects.

BRIEF SUMMARY

One embodiment is a stimulation lead that includes a lead body having alongitudinal length, a distal portion, and a proximal portion; terminalsdisposed along the proximal portion of the lead body; an electrodecarrier coupled to, or disposed along, the distal portion of the leadbody; segmented electrodes disposed along the electrode carrier; andconductors extending along the lead body and coupling the segmentedelectrodes to the terminals. The electrode carrier includes a latticeregion defining segmented electrode receiving openings. Each of thesegmented electrodes extends around no more than 75% of a circumferenceof the lead and is disposed in a different one of the segmentedelectrode receiving openings of the electrode carrier. Optionally, thestimulation lead can include one or more ring electrodes disposed on theelectrode carrier and coupled via one or more conductors to theterminals.

Another embodiment is a method of making a stimulation lead. The methodincludes providing an electrode carrier having a lattice region definingmultiple segmented electrodes receiving openings; and disposingsegmented electrodes in the segmented electrode receiving openings. Eachof the segmented electrodes extends around no more than 75% of acircumference of the lead and each of the segmented electrodes isdisposed in a different one of the segmented electrode receivingopenings of the electrode carrier. The method also includes electricallycoupling conductors to the segmented electrodes and electricallycoupling the conductors to terminals disposed along an opposing end ofthe lead. Optionally, the method can include disposing one or more ringelectrodes on the electrode carrier and electrically coupling the one ormore ring electrodes to the terminals via one or more conductors.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic side view of one embodiment of a device for brainstimulation, according to the invention;

FIG. 2 is a schematic diagram of radial current steering along variouselectrode levels along the length of a lead, according to the invention;

FIG. 3A is a perspective view of an embodiment of a portion of a leadhaving a plurality of segmented electrodes, according to the invention:

FIG. 3B is a perspective view of a second embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention:

FIG. 3C is a perspective view of a third embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3D is a perspective view of a fourth embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention:

FIG. 4 is a schematic perspective view of one embodiment of an electrodecarrier, according to the invention:

FIG. 5A is a schematic exploded perspective view of one embodiment of aportion of lead illustrating an electrode carrier and associatedsegmented and ring electrodes, according to the invention:

FIG. 5B is a schematic exploded perspective view of one embodiment of aportion of lead illustrating an electrode carrier and selected segmentedand ring electrodes with associated conductors, according to theinvention; and

FIG. 5C is a schematic perspective view of one embodiment of a portionof a lead showing the electrode carrier with electrodes attached to aremainder of the lead, according to the invention.

DETAILED DESCRIPTION

The invention is directed to the area of electrical stimulation systemsand methods of making and using the systems. The present invention isalso directed to electrical stimulation leads with segmented electrodesthat can be used for directed electrical stimulation, as well as methodsof making and using the segmented electrodes, leads, and electricalstimulation systems.

A lead for deep brain stimulation may include stimulation electrodes,recording electrodes, or a combination of both. At least some of thestimulation electrodes, recording electrodes, or both are provided inthe form of segmented electrodes that extend only partially around thecircumference of the lead. These segmented electrodes can be provided insets of electrodes, with each set having electrodes radially distributedabout the lead at a particular longitudinal position. For illustrativepurposes, the leads are described herein relative to use for deep brainstimulation, but it will be understood that any of the leads can be usedfor applications other than deep brain stimulation, including spinalcord stimulation, peripheral nerve stimulation, or stimulation of othernerves and tissues.

Suitable implantable electrical stimulation systems include, but are notlimited to, a least one lead with one or more electrodes disposed on adistal end of the lead and one or more terminals disposed on one or moreproximal ends of the lead. Leads include, for example, percutaneousleads. Examples of electrical stimulation systems with leads are foundin, for example, U.S. Pat. Nos. 6,181,969; 6,516,227; 6,609,029;6,609,032; 6,741,892; 7,244,150; 7,450,997; 7,672,734; 7,761,165;7,783,359; 7,792,590; 7,809,446; 7,949,395; 7,974,706; 8,175,710;8,224,450; 8,271,094; 8,295,944; 8,364,278; and 8,391,985; U.S. PatentApplications Publication Nos. 2007/0150036; 2009/0187222; 2009/0276021;2010/0076535; 2010/0268298; 2011/0004267; 2011/0078900; 2011/0130817;2011/0130818; 2011/0238129; 2011/0313500; 2012/0016378; 2012/0046710;2012/0071949; 2012/0165911; 2012/0197375; 2012/0203316; 2012/0203320;2012/0203321; 2012/0316615; and 2013/0105071; and U.S. patentapplication Ser. Nos. 12/177,823 and 13/750,725, all of which areincorporated by reference.

In at least some embodiments, a practitioner may determine the positionof the target neurons using recording electrode(s) and then position thestimulation electrode(s) accordingly. In some embodiments, the sameelectrodes can be used for both recording and stimulation. In someembodiments, separate leads can be used; one with recording electrodeswhich identify target neurons, and a second lead with stimulationelectrodes that replaces the first after target neuron identification.In some embodiments, the same lead may include both recording electrodesand stimulation electrodes or electrodes may be used for both recordingand stimulation.

FIG. 1 illustrates one embodiment of a device 100 for brain stimulation.The device includes a lead 110, a plurality of electrodes 125 disposedat least partially about a circumference of the lead 110, a plurality ofterminals 135, a connector 132 for connection of the electrodes to acontrol unit, and a stylet 140 for assisting in insertion andpositioning of the lead in the patient's brain. The stylet 140 can bemade of a rigid material. Examples of suitable materials for the styletinclude, but are not limited to, tungsten, stainless steel, and plastic.The stylet 140 may have a handle 150 to assist insertion into the lead110, as well as rotation of the stylet 140 and lead 110. The connector132 fits over a proximal end of the lead 110, preferably after removalof the stylet 140.

The control unit (not shown) is typically an implantable pulse generatorthat can be implanted into a patient's body, for example, below thepatient's clavicle area. The pulse generator can have eight stimulationchannels which may be independently programmable to control themagnitude of the current stimulus from each channel. In some cases thepulse generator may have more or fewer than eight stimulation channels(e.g., 4-, 6-, 16-, 32-, or more stimulation channels). The control unitmay have one, two, three, four, or more connector ports, for receivingthe plurality of terminals 135 at the proximal end of the lead 110.

In one example of operation, access to the desired position in the braincan be accomplished by drilling a hole in the patient's skull or craniumwith a cranial drill (commonly referred to as a burr), and coagulatingand incising the dura mater, or brain covering. The lead 110 can beinserted into the cranium and brain tissue with the assistance of thestylet 140. The lead 110 can be guided to the target location within thebrain using, for example, a stereotactic flame and a microdrive motorsystem. In some embodiments, the microdrive motor system can be fully orpartially automatic. The microdrive motor system may be configured toperform one or more the following actions (alone or in combination):insert the lead 110, retract the lead 110, or rotate the lead 110.

In some embodiments, measurement devices coupled to the muscles or othertissues stimulated by the target neurons, or a unit responsive to thepatient or clinician, can be coupled to the control unit or microdrivemotor system. The measurement device, user, or clinician can indicate aresponse by the target muscles or other tissues to the stimulation orrecording electrode(s) to further identify the target neurons andfacilitate positioning of the stimulation electrode(s). For example, ifthe target neurons are directed to a muscle experiencing tremors, ameasurement device can be used to observe the muscle and indicatechanges in tremor frequency or amplitude in response to stimulation ofneurons. Alternatively, the patient or clinician may observe the muscleand provide feedback.

The lead 110 for deep brain stimulation can include stimulationelectrodes, recording electrodes, or both. In at least some embodiments,the lead 110 is rotatable so that the stimulation electrodes can bealigned with the target neurons after the neurons have been locatedusing the recording electrodes.

Stimulation electrodes may be disposed on the circumference of the lead110 to stimulate the target neurons. Stimulation electrodes may bering-shaped so that current projects from each electrode equally inevery direction from the position of the electrode along a length of thelead 110. Ring electrodes typically do not enable stimulus current to bedirected to only one side of the lead. Segmented electrodes, however,can be used to direct stimulus current to one side, or even a portion ofone side, of the lead. When segmented electrodes are used in conjunctionwith an implantable pulse generator that delivers constant currentstimulus, current steering can be achieved to more precisely deliver thestimulus to a position around an axis of the lead (i.e., radialpositioning around the axis of the lead).

To achieve current steering, segmented electrodes can be utilized inaddition to, or as an alternative to, ring electrodes. Though thefollowing description discusses stimulation electrodes, it will beunderstood that all configurations of the stimulation electrodesdiscussed may be utilized in arranging recording electrodes as well.

The lead 100 includes a lead body 110, one or more optional ringelectrodes 120, and a plurality of sets of segmented electrodes 130. Thelead body 110 can be formed of a biocompatible, non-conducting materialsuch as, for example, a polymeric material. Suitable polymeric materialsinclude, but are not limited to, silicone, polyurethane, polyurea,polyurethane-urea, polyethylene, or the like. Once implanted in thebody, the lead 100 may be in contact with body tissue for extendedperiods of time. In at least some embodiments, the lead 100 has across-sectional diameter of no more than 1.5 mm and may be in the rangeof 1 to 1.5 mm. In at least some embodiments, the lead 100 has a lengthof at least 10 cm and the length of the lead 100 may be in the range of25 to 70 cm.

The electrodes may be made using a metal, alloy, conductive oxide, orany other suitable conductive biocompatible material. Examples ofsuitable materials include, but are not limited to, platinum, platinumiridium alloy, iridium, titanium, tungsten, palladium, palladiumrhodium, or the like. Preferably, the electrodes are made of a materialthat is biocompatible and does not substantially corrode under expectedoperating conditions in the operating environment for the expectedduration of use.

Each of the electrodes can either be used or unused (OFF). When theelectrode is used, the electrode can be used as an anode or cathode andcarry anodic or cathodic current. In some instances, an electrode mightbe an anode for a period of time and a cathode for a period of time.

Stimulation electrodes in the form of ring electrodes 120 may bedisposed on any part of the lead body 110, usually near a distal end ofthe lead 100. In FIG. 1, the lead 100 includes two ring electrodes 120.Any number of ring electrodes 120 may be disposed along the length ofthe lead body 110 including, for example, one, two three, four, live,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, sixteen or more ring electrodes 120. It will be understood thatany number of ring electrodes may be disposed along the length of thelead body 110. In some embodiments, the ring electrodes 120 aresubstantially cylindrical and wrap around the entire circumference ofthe lead body 110. In some embodiments, the outer diameters of the ringelectrodes 120 are substantially equal to the outer diameter of the leadbody 110. The length of the ring electrodes 120 may vary according tothe desired treatment and the location of the target neurons. In someembodiments the length of the ring electrodes 120 are less than or equalto the diameters of the ring electrodes 120. In other embodiments, thelengths of the ring electrodes 120 are greater than the diameters of thering electrodes 120.

Deep brain stimulation leads may include one or more sets of segmentedelectrodes. Segmented electrodes may provide for superior currentsteering than ring electrodes because target structures in deep brainstimulation are not typically symmetric about the axis of the distalelectrode array. Instead, a target may be located on one side of a planerunning through the axis of the lead. Through the use of a radiallysegmented electrode array (“RSEA”), current steering can be performednot only along a length of the lead but also around a circumference ofthe lead. This provides precise three-dimensional targeting and deliveryof the current stimulus to neural target tissue, while potentiallyavoiding stimulation of other tissue. Examples of leads with segmentedelectrodes include U.S. Pat. Nos. 8,295,944; and 8,391,985; and U.S.Patent Applications Publication Nos. 2011/0005069; 2010/0268298;2011/0130817; 2011/0130818; 2011/0078900; 2011/0238129; 2011/0313500;2012/0016378; 2012/0046710; 2012/0165911; 2012/0197375; 2012/0203316;2012/0203320; and 2012/0203321, all of which are incorporated herein byreference.

In FIG. 1, the lead 100 is shown having a plurality of segmentedelectrodes 130. Any number of segmented electrodes 130 may be disposedon the lead body 110 including, for example, one, two three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, sixteen or more segmented electrodes 130. It will be understoodthat any number of segmented electrodes 130 may be disposed along thelength of the lead body 110. A segmented electrode 130 typically extendsonly 75%, 67%, 60%, 50%, 40%, 33%, 25%, 20%, 17%, 15%, or less aroundthe circumference of the lead.

The segmented electrodes 130 may be grouped into sets of segmentedelectrodes, where each set is disposed around a circumference of thelead 100 at a particular longitudinal portion of the lead 100. The lead100 may have any number segmented electrodes 130 in a given set ofsegmented electrodes. The lead 100 may have one, two, three, four, five,six, seven, eight, or more segmented electrodes 130 in a given set. Inat least some embodiments, each set of segmented electrodes 130 of thelead 100 contains the same number of segmented electrodes 130. Thesegmented electrodes 130 disposed on the lead 100 may include adifferent number of electrodes than at least one other set of segmentedelectrodes 130 disposed on the lead 100.

The segmented electrodes 130 may vary in size and shape. In someembodiments, the segmented electrodes 130 are all of the same size,shape, diameter, width or area or any combination thereof. In someembodiments, the segmented electrodes 130 of each circumferential set(or even all segmented electrodes disposed on the lead 100) may beidentical in size and shape.

Each set of segmented electrodes 130 may be disposed around thecircumference of the lead body 110 to form a substantially cylindricalshape around the lead body 110. The spacing between individualelectrodes of a given set of the segmented electrodes may be the same,or different from, the spacing between individual electrodes of anotherset of segmented electrodes on the lead 100. In at least someembodiments, equal spaces, gaps or cutouts are disposed between eachsegmented electrode 130 around the circumference of the lead body 110.In other embodiments, the spaces, gaps or cutouts between the segmentedelectrodes 130 may differ in size or shape. In other embodiments, thespaces, gaps, or cutouts between segmented electrodes 130 may be uniformfor a particular set of the segmented electrodes 130, or for all sets ofthe segmented electrodes 130. The sets of segmented electrodes 130 maybe positioned in irregular or regular intervals along a length the leadbody 110.

Conductor wires that attach to the ring electrodes 120 or segmentedelectrodes 130 extend along the lead body 110. These conductor wires mayextend through the material of the lead 100 or along one or more lumensdefined by the lead 100, or both. The conductor wires are presented at aconnector (via terminals) for coupling of the electrodes 120, 130 to acontrol unit (not shown).

When the lead 100 includes both ring electrodes 120 and segmentedelectrodes 130, the ring electrodes 120 and the segmented electrodes 130may be arranged in any suitable configuration. For example, when thelead 100 includes two sets of ring electrodes 120 and two sets ofsegmented electrodes 130, the ring electrodes 120 can flank the two setsof segmented electrodes 130 (see e.g., FIG. 1). Alternately, the twosets of ring electrodes 120 can be disposed proximal to the two sets ofsegmented electrodes 130 (see e.g., FIG. 3C), or the two sets of ringelectrodes 120 can be disposed distal to the two sets of segmentedelectrodes 130 (see e.g., FIG. 3D). It will be understood that otherconfigurations are possible as well (e.g., alternating ring andsegmented electrodes, or the like).

By varying the location of the segmented electrodes 130, differentcoverage of the target neurons may be selected. For example, theelectrode arrangement of FIG. 3C may be useful if the physiciananticipates that the neural target will be closer to a distal tip of thelead body 110, while the electrode arrangement of FIG. 3D may be usefulif the physician anticipates that the neural target will be closer to aproximal end of the lead body 110.

Any combination of ring electrodes 120 and segmented electrodes 130 maybe disposed on the lead 100. For example, the lead may include a firstring electrode 120, two sets of segmented electrodes; each set formed offour segmented electrodes 130, and a final ring electrode 120 at the endof the lead. This configuration may simply be referred to as a 1-4-4-1configuration. It may be useful to refer to the electrodes with thisshorthand notation. Thus, the embodiment of FIG. 3C may be referred toas a 1-1-4-4 configuration, while the embodiment of FIG. 3D may bereferred to as a 4-4-1-1 configuration. Other electrode configurationsinclude, for example, a 2-2-2-2 configuration, where four sets ofsegmented electrodes are disposed on the lead, and a 4-4 configuration,where two sets of segmented electrodes, each having four segmentedelectrodes 130 are disposed on the lead. In some embodiments, the leadincludes 16 electrodes. Possible configurations for a 16-electrode leadinclude, but are not limited to 4-4-4-4; 8-8; 3-3-3-3-3-1 (and allrearrangements of this configuration); and 2-2-2-2-2-2-2.

FIG. 2 is a schematic diagram to illustrate radial current steeringalong various electrode levels along the length of the lead 200. Whileconventional lead configurations with ring electrodes are only able tosteer current along the length of the lead (the z-axis), the segmentedelectrode configuration is capable of steering current in the x-axis,r-axis as well as the z-axis. Thus, the centroid of stimulation may besteered in any direction in the three-dimensional space surrounding thelead 200. In some embodiments, the radial distance, r, and the angle θaround the circumference of the lead 200 may be dictated by thepercentage of anodic current (recognizing that stimulation predominantlyoccurs near the cathode, although strong anodes may cause stimulation aswell) introduced to each electrode. In at least some embodiments, theconfiguration of anodes and cathodes along the segmented electrodesallows the centroid of stimulation to be shifted to a variety ofdifferent locations along the lead 200.

As can be appreciated from FIG. 2, the centroid of stimulation can beshifted at each level along the length of the lead 200. The use ofmultiple sets of segmented electrodes at different levels along thelength of the lead allows for three-dimensional current steering. Insome embodiments, the sets of segmented electrodes are shiftedcollectively (i.e., the centroid of simulation is similar at each levelalong the length of the lead). In at least some other embodiments, eachset of segmented electrodes is controlled independently. Each set ofsegmented electrodes may contain two, three, four, five, six, seven,eight or more segmented electrodes. It will be understood that differentstimulation profiles may be produced by varying the number of segmentedelectrodes at each level. For example, when each set of segmentedelectrodes includes only two segmented electrodes, uniformly distributedgaps (inability to stimulate selectively) may be formed in thestimulation profile. In some embodiments, at least three segmentedelectrodes 230 in a set are utilized to allow for true 360° selectivity.

As previously indicated, the foregoing configurations may also be usedwhile utilizing recording electrodes. In some embodiments, measurementdevices coupled to the muscles or other tissues stimulated by the targetneurons or a unit responsive to the patient or clinician can be coupledto the control unit or microdrive motor system. The measurement device,user, or clinician can indicate a response by the target muscles orother tissues to the stimulation or recording electrodes to furtheridentify the target neurons and facilitate positioning of thestimulation electrodes. For example, if the target neurons are directedto a muscle experiencing tremors, a measurement device can be used toobserve the muscle and indicate changes in tremor frequency or amplitudein response to stimulation of neurons. Alternatively, the patient orclinician may observe the muscle and provide feedback.

The reliability and durability of the lead will depend heavily on thedesign and method of manufacture. Fabrication techniques discussed belowprovide methods that can produce manufacturable and reliable leads.

Returning to FIG. 1, when the lead 100 includes a plurality of sets ofsegmented electrodes 130, it may be desirable to form the lead 100 suchthat corresponding electrodes of different sets of segmented electrodes130 are radially aligned with one another along the length of the lead100 (see e.g., the segmented electrodes 130 shown in FIG. 1). Radialalignment between corresponding electrodes of different sets ofsegmented electrodes 130 along the length of the lead 100 may reduceuncertainty as to the location or orientation between correspondingsegmented electrodes of different sets of segmented electrodes.Accordingly, it may be beneficial to form electrode arrays such thatcorresponding electrodes of different sets of segmented electrodes alongthe length of the lead 100 are radially aligned with one another and donot radially shift in relation to one another during manufacturing ofthe lead 100.

In other embodiments, individual electrodes in the two sets of segmentedelectrodes 130 are staggered (see. FIG. 3B) relative to one anotheralong the length of the lead body 110. In some cases, the staggeredpositioning of corresponding electrodes of different sets of segmentedelectrodes along the length of the lead 100 may be designed for aspecific application.

Segmented electrodes can be used to tailor the stimulation region sothat, instead of stimulating tissue around the circumference of the leadas would be achieved using a ring electrode, the stimulation region canbe directionally targeted. In some instances, it is desirable to targeta parallelepiped (or slab) region 250 that contains the electrodes ofthe lead 200, as illustrated in FIG. 2. One arrangement for directing astimulation field into a parallelepiped region uses segmented electrodesdisposed on opposite sides of a lead.

FIGS. 3A-3D illustrate leads 300 with segmented electrodes 330, optionalring electrodes 320, and a lead body 310. The sets of segmentedelectrodes 330 include either two (FIG. 3B) or four (FIGS. 3A. 3C, and3D) or any other number of segmented electrodes including, for example,three, five, six, or more.

Any other suitable arrangements of segmented electrodes can be used. Asan example, arrangements in which segmented electrodes are arrangedhelically with respect to each other. One embodiment includes a doublehelix.

One challenge to making leads with segmented electrodes is the correctplacement of the electrodes, and retention of the desired electrodeplacement, during the manufacturing process. An electrode carrier can beutilized to hold the electrodes in the desired spatial arrangementduring the manufacture of the lead. The electrode carrier is made of anon-conductive material to electrically isolate the segmented electrodesfrom each other and from the ring electrodes, if present.

FIG. 4 illustrates one embodiment of an electrode carrier 450. Theelectrode carrier 450 includes a lattice region 452 that definessegmented electrode receiving openings 454 where the segmentedelectrodes are to be placed (see, for example, FIG. 5). In theillustrated example, lattice region 452 of the electrode carrier 450 isdesigned for two sets of segmented electrodes with each set having threesegmented electrodes. It will be recognized that other electrodecarriers can be designed that include a different number of sets ofsegmented electrodes, a different number of segmented electrodes in aset, or a different spatial arrangement of the segmented electrodes(e.g., with sets staggered with respect to each other or with some orall of the segmented electrodes not arranged in sets), or anycombination thereof.

The electrode carrier 450 may also include one or more tubular features456 to receive a ring electrode (see, for example, FIG. 5A). The tubularfeatures 456 may be provided on the proximal or distal ends (or bothends as illustrated in FIG. 4) of the electrode carrier 450.Alternatively or additionally, one or more tubular features can beprovided at other locations on the electrode carrier if the ringelectrode can be disposed around the tubular feature (for example, ifthe electrode has a “C” shape, or is a flexible strip, and can bewrapped, snapped, crimped, adhered, or otherwise disposed or fastenedaround the tubular feature.) In some embodiments, the distal-most ringelectrode may be a tip electrode which has a closed end. Examples of atip electrode can be found at, for example, U.S. patent application Ser.No. 13/906,776, incorporated herein by reference.

The electrode carrier 450 may also have a central lumen 458 throughwhich conductors (see, FIG. 5B) attached to the segmented electrodes orring electrodes can pass on the way to the remainder of the lead. Thecentral lumen 458 may be open at both ends of the electrode carrier 450or may be closed at the distal end of the electrode carrier.

The electrode carrier 450, or at least the lattice region 452, is formedof a non-conductive material which may be the same material as the leadbody, for example, silicone, polyurethane, polyetheretherketone, or anyother suitable biocompatible material. In some embodiments, theelectrode carrier 450 may be made of a material that is stiffer orharder than the material of the lead body. For example, the material ofthe electrode carrier 450 may have a higher durometer than that of thelead body. In some embodiments, the electrode carrier 450 is made of thesame type of polymer material (e.g., polyurethane or silicone) as thelead body, but with a higher durometer than the lead body. A stiffer orharder material for the electrode carrier may facilitate manufacturing.

Optionally, the electrode carrier 450 may be designed to allow a user tobreak the electrode carrier at predefined positions, such as one or moreof breakage positions 460 a, 460 b. 460 c. It will be understood thatany of these positions, alone or in combination, may be selected for abreakage position or one or more other positions may be selected. Theelectrode carrier at the one or more breakage positions may be weakened.For example, the electrode carrier may have perforations, indentations,grooves, striations, or other arrangements that allow a user to breakthe carrier at the predefined positions. In at least some embodiments,breakage at these positions may occur, for example, after formation ofthe lead body or just prior to implantation. It will be understood thateven if the breakage position is present in the electrode carrier,breakage of the electrode carrier does not necessarily occur. Thebreakage of the carrier at one or more breakage positions may reduce thestiffness of the lead at the distal end where the carrier resides. Thestiffness of the carrier may be desirable during manufacture, but lessdesirable when the lead is implanted.

FIG. 5A is an exploded view of an electrode carrier 550, segmentedelectrodes 530, ring electrodes 520, and a portion of the lead 570. Thearrows in FIG. 5A indicate the places that the electrodes 520, 530 areattached onto the electrode carrier 550.

The segmented electrodes 530 fit into the segmented electrode receivingopenings 554 of the lattice portion 552 of the electrode carrier 550. Insome embodiments, the segmented electrodes 530 may form a friction fitwith, or snap into, the lattice portion 552 surrounding the respectivesegmented electrode receiving openings 554. In other embodiments, thesegmented electrodes 530 may be held within the openings 554 merely byapplying tension to conductors (see FIG. 5B) attached to the segmentedelectrodes. In some embodiments, adhesive or other fastening mechanismsmay be used to hold the segmented electrodes in place once positioned.

The ring electrodes 530 fit onto the tubular features 556 of theelectrode carrier 550. In some embodiments, the ring electrodes 520 mayform a friction fit with, or snap onto, the tubular features 556. Inother embodiments, the ring electrodes 520 may be held on the tubularfeatures 556 merely by applying tension to conductors (see FIG. 5B)attached to the ring electrodes. In some embodiments, adhesive or otherfastening mechanisms may be used to hold the ring electrodes in placeonce positioned.

In some embodiments, the other surface of the segmented electrodes 530and the outer surface of the lattice portion 552 of the electrodecarrier 550 may form an isodiametric arrangement when the segmentedelectrodes are nested in the segmented electrode receiving openings 554.Optionally, the outer surface of the lattice portion 552 may also beisodiametric with the outer surface of the ring electrodes 520 when thering electrodes 520 are seated on the tubular features 556 of theelectrode carrier 550.

In other embodiments, the outer surface of the lattice portion 552 maybe recessed with respect to the outer surface of the segmentedelectrodes 552 when the segmented electrodes are nested in the segmentedelectrode receiving openings 554. Optionally, the outer surface of thelattice portion 552 may also be recessed with respect to the outersurface of the ring electrodes 520 when the ring electrodes 520 areseated on the tubular features 556 of the electrode carrier 550. Sucharrangements may facilitate the formation of a portion of the lead body(for example, a jacket) between the segmented electrodes (and optionallybetween the ring electrodes and adjacent segmented electrodes) and overthe lattice portion of the electrode carrier.

In some embodiments, the longitudinal length of one or more of thetubular features 556 is equal to the longitudinal length of the ringelectrode 520 positioned thereon. In some embodiments, the longitudinallength of one or more of the tubular features 556 is less than thelongitudinal length of the ring electrode 520 positioned thereon. Thismay facilitate attachment to a portion of the lead 570 to the electrodecarrier and electrodes using the proximal-most ring electrode forattachment or may facilitate attachment of an end cap (not shown) usingthe distal-most ring electrode for attachment. In some embodiments, thelongitudinal length of one or more of the tubular features 556 isgreater than the longitudinal length of the ring electrode 520positioned thereon. This may facilitate attachment to a portion of thelead 570 to the electrode carrier and electrodes using the proximal-mosttubular feature for attachment or may facilitate attachment of an endcap (see. FIG. 1 for lead with end cap distal to ring electrode) usingthe distal-most tubular feature for attachment.

FIG. 5B illustrates one embodiment of a ring electrode 520 and asegmented electrode 530 each electrically coupled to a respectiveconductor 521, 531. The conductors 521, 531 can be attached to therespective electrodes 520, 530 using any suitable method including, butnot limited to, welding, soldering, adhesively attaching, or the like.Only these two electrodes are illustrated for clarity, but it will beunderstood that each of the other electrodes (see FIG. 5A) can besimilarly attached to a conductor.

The conductor 521 is threaded through the central lumen 558 of theelectrode carrier 550 to the portion of the lead 570. The conductor 531is threaded through the segmented electrode receiving opening 554 thatis to receive the segmented electrode 530. The conductor 531 proceedsthrough the central lumen 558 to the portion of the lead 570. In someembodiments, the electrodes 520, 530 may be held on the electrodecarrier 550 by applying tension to the conductors 521, 531 attached tothe electrodes. It will be understood that the conductors 521, 531 canbe attached to the electrodes 520, 530 prior to or after threading theconductors through the electrode carrier 550. It will also be understoodthat the conductors 521, 531 can be attached to the electrodes 520, 530prior to or after threading the conductors into the portion of the lead570.

The lead 570 may include a conductor tube 572 that carries theconductors through the lead to its proximal end. In the illustratedembodiment, the conductor tube 572 includes peripheral lumens 574surrounding a central lumen 576. Each of the peripheral lumens can carryone or more conductors and the central lumen can carry one or moreconductors or may be useful as a stylet lumen. In some embodiments, eachconductor 521, 531 is threaded through a different one of the peripherallumens.

FIG. 5C illustrated one embodiment of a lead 570 with the electrodecarrier 550 disposed on the lead and the electrodes 520, 530 seated inthe electrode carrier. In some embodiments, the electrode carrier 550may form part of the exterior surface of the lead body. In otherembodiments, a lead body may be formed over the electrode carrier (see.FIG. 1).

The above specification, examples, and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A stimulation lead, comprising: a lead bodycomprising a longitudinal length, a distal portion, and a proximalportion; a plurality of terminals disposed along the proximal portion ofthe lead body; a single electrode carrier coupled to, or disposed along,the distal portion of the lead body, the electrode carrier comprising alattice region defining a plurality of segmented electrode receivingopenings, wherein the lattice region is formed of a non-conductivematerial, wherein the segmented electrode receiving openings arearranged in a plurality of sets with each of the sets being disposed ata different longitudinal position along the lead and comprising two ormore of the segmented electrode receiving openings, wherein theplurality of sets comprises a first set and a second set adjacent to thefirst set, wherein the lead body and the electrode carrier are formed ofdifferent materials; a plurality of electrodes comprising a plurality ofsegmented electrodes, each of the segmented electrodes disposed in adifferent one of the segmented electrode receiving openings of theelectrode carrier; and a plurality of conductors extending along thelead body and coupling the plurality of electrodes to the plurality ofterminals.
 2. The stimulation lead of claim 1, wherein the plurality ofelectrodes further comprises a first ring electrode, wherein theelectrode carrier comprises a proximal portion disposed proximal to allof the segmented electrodes, wherein the first ring electrode isdisposed on the proximal portion of the electrode carrier and separatedfrom each of the segmented electrodes by the electrode carrier, whereinthe proximal portion of the electrode carrier is radially beneath thefirst ring electrode.
 3. The stimulation lead of claim 2, wherein theplurality of electrodes comprises a second ring electrode and theelectrode carrier comprises a distal portion disposed distal to all ofthe segmented electrodes, wherein the second ring electrode is disposedon the distal portion of the electrode carrier and separated from eachof the segmented electrodes by the electrode carrier.
 4. The stimulationlead of claim 1, wherein the plurality of electrodes further comprises afirst ring electrode, wherein the electrode carrier comprises a distalportion disposed distal to all of the segmented electrodes, wherein thefirst ring electrode is disposed on the distal portion of the electrodecarrier and separated from each of the segmented electrodes by theelectrode carrier, wherein the distal portion of the electrode carrieris radially beneath the first ring electrode.
 5. The stimulation lead ofclaim 1, wherein the electrode carrier further comprises at least onebreakage position configured and arranged to be weakened relative toadjacent portions of the electrode carrier to permit breakage of theelectrode carrier after manufacture of the stimulation lead.
 6. Thestimulation lead of claim 5, wherein the at least one breakage positioncomprises a first breakage position disposed between two of the sets ofthe segmented electrode receiving openings.
 7. The stimulation lead ofclaim 6, wherein the plurality of electrodes further comprises a firstring electrode disposed on the carrier and the at least one breakageposition comprises a second breakage position disposed between one ofthe sets of the segmented electrode receiving openings and the firstring electrode.
 8. The stimulation lead of claim 1, wherein theelectrode carrier defines a central lumen through which at least aportion of the plurality of conductors passes.
 9. A stimulation lead,comprising: a lead body comprising a longitudinal length, a distalportion, and a proximal portion; a plurality of terminals disposed alongthe proximal portion of the lead body; a single electrode carriercoupled to, or disposed along, the distal portion of the lead body, theelectrode carrier comprising a lattice region defining a plurality ofsegmented electrode receiving openings, wherein the lattice region isformed of a non-conductive material, wherein the lead body and theelectrode carrier are formed of different materials; a plurality ofelectrodes comprising a plurality of segmented electrodes, each of thesegmented electrodes disposed in a different one of the segmentedelectrode receiving openings of the electrode carrier; and a pluralityof conductors extending along the lead body and coupling the pluralityof electrodes to the plurality of terminals.
 10. The stimulation lead ofclaim 9, wherein the plurality of electrodes further comprises a firstring electrode, wherein the electrode carrier comprises a proximalportion disposed proximal to all of the segmented electrodes, whereinthe first ring electrode is disposed on the proximal portion of theelectrode carrier and separated from each of the segmented electrodes bythe electrode carrier, wherein the proximal portion of the electrodecarrier is radially beneath the first ring electrode.
 11. Thestimulation lead of claim 10, wherein the plurality of electrodescomprises a second ring electrode and the electrode carrier comprises adistal portion disposed distal to all of the segmented electrodes,wherein the second ring electrode is disposed on the distal portion ofthe electrode carrier and separated from each of the segmentedelectrodes by the electrode carrier.
 12. The stimulation lead of claim9, wherein the electrode carrier further comprises at least one breakageposition configured and arranged to be weakened relative to adjacentportions of the electrode carrier to permit breakage of the electrodecarrier after manufacture of the stimulation lead.
 13. The stimulationlead of claim 12, wherein the at least one breakage position comprises afirst breakage position disposed between two of the segmented electrodereceiving openings.
 14. The stimulation lead of claim 13, wherein theplurality of electrodes further comprises a first ring electrodedisposed on the carrier and the at least one breakage position comprisesa second breakage position disposed between one of the segmentedelectrode receiving openings and the first ring electrode.
 15. Thestimulation lead of claim 9, wherein the electrode carrier defines acentral lumen through which at least a portion of the plurality ofconductors passes.
 16. A electrical stimulation system, comprising: theelectrical stimulation lead of claim 1; and a control module coupleableto the electrical stimulation lead, the control module comprising ahousing, and an electronic subassembly disposed in the housing andconfigured and arranged to generate and direct electrical stimulation tothe electrodes of the electrical stimulation lead.
 17. A electricalstimulation system, comprising: the electrical stimulation lead of claim9; and a control module coupleable to the electrical stimulation lead,the control module comprising a housing, and an electronic subassemblydisposed in the housing and configured and arranged to generate anddirect electrical stimulation to the electrodes of the electricalstimulation lead.
 18. The stimulation lead of claim 1, wherein thesegmented electrode receiving openings of the first set are staggeredwith respect to the segmented electrode receiving openings of the secondset.
 19. The stimulation lead of claim 1, wherein the lead body and thecarrier are made using polyurethane, but the polyurethane of the carrierhas a higher durometer than the polyurethane of the lead body.
 20. Thestimulation lead of claim 9, wherein the segmented electrode receivingopenings are arranged in a double helix.